1. Field of the Invention
The present invention relates to the technical field of decoration materials for buildings, and more particularly to an exterior wall decorative foam panel made of foam and used for attaching onto a surface of an interior wall.
2. Description of the Related Art
Exterior wall decorative foam originates from the United States, and it is a new construction material used to replace conventional construction materials including wood and anticorrosive wood. The exterior wall decorative foam has the advantages of corrosion resistance, low maintenance, low deformation, waterproof as well as the anti-mildew, anti-pest, fire retardant and thermal insulation effects. In addition, 100% of the discarded material of the exterior wall decorative foam can be recycled and reused. Thus, the exterior wall decorative foam can meet the requirements of green economy, low-carbon consumption, environmental protection and recycle and reuse, and it gradually becomes a popular material in Europe and the United States.
As disclosed in U.S. Pat. No. 7,748,183 entitled “System, methods and compositions for attaching paneling to a building surface,” disclosing the panel has an upper interlocking member and a lower interlocking member disposed at an upper end and a lower end of the panel respectively and a side interlocking member disposed on both sides of the panel separately, wherein the upper interlocking members and the lower interlocking members of two opposite panels and the side interlocking members on both sides are bevels combined by a tongue-and-groove joint with a contact angle of between 22.5 and 77.5 degrees to achieve a tight connection each other. The panel further comprises a plurality of weep channels and a plurality of air chambers formed on the back surface of the panel to achieve the water drainage and air circulation effects.
However, the length of the bevel and the tongue-and-groove joint varies with the contact angle. The smaller the contact angle, the greater is the length of the bevel and the tongue-and-groove joint, and the smaller is the thickness, so that the decorative external wall may be cracked or broken easily during transportation. On the other hand, the greater the contact angle, the smaller is the length of the bevel and the tongue-and-groove joint, so that the interlocking effect may be affected adversely. Thus, the most preferred contact angle is 45 degrees. Since the foam material is porous and has a waterproof effect that does not absorb water as water is stored in the crevices of the panels, therefore the issues of the mildew, fouling and moss may arise. Although the panel comes with the design of the weep channels, the foregoing issues still exists because the aspect ratio of the panel is a too-large, so that it is necessary to increase the thickness of the material or add a reinforcing material to enhance the overall strength. The increased thickness results in an increased depth of the air chambers and an uneasy drainage. Further, the increased thickness also causes an increase of weight and incurs a higher cost. Obviously, the conventional exterior wall decorative foam panel requires improvements.